Cerny et al., U.S. Pat. No. 5,298,894, discloses a mobile automatic meter reading (AMR) system in which a utility meter transmitter receives pulses from a pulse transducer installed on a utility meter and transmits radio frequency (RF) meter data signals to an RF collection unit in a drive-by vehicle. In these mobile AMR systems, a vehicle or a person on foot with an RF collection unit (a walk-by collection system) can move through a neighborhood and collect a large number of readings per hour without entering any of the property of the customers.
Gastouniotis et al., U.S. Pat. No. 4,940,976, discloses a communications network for transmitting data from a plurality of remote meters to a central station through a plurality of fixed receiving stations. In fixed receiver network systems today, the receiver units can be mounted on utility poles, inside of electric meters or in utility pedestals. In such systems, it is not necessary to provide people and equipment to travel through the areas where readings are to be collected. There are, however, other issues is locating receivers and providing other equipment, such as repeaters, to provide coverage of the entire geographic area being serviced.
Mobile collection units and their associated transmitters operate in the unlicensed band around 915 Mhz, where transmissions are only required to reach distances of a few hundred feet, but must be sent out frequently to be available for a drive-by or walk-by collection unit at random times of collection. The unlicensed band is in a narrow range of the radio frequency spectrum, where power associated with the transmission signals is limited, to prevent interference in various areas where the equipment is operating with other RF signals in the environment. Fixed networks, on the other hand, transmit signals over distances of more than 1,000 feet and up to distances of one-half mile or more. Fixed network transmitters typically utilize a frequency-hopping, spread-spectrum type of transmission, which by regulation is permitted to use transmitter power levels 1000 times greater than the narrow band systems.
Mobile data collection systems and fixed data collection systems are competing in the marketplace today as gas, electric and water utilities move toward automation in the collection of metering data and the billing of utility customers.
Many utilities purchasing automatic meter reading systems today must consider system issues over a period of years. It would therefore be beneficial to the acceptance of such systems to provide these customers with the maximum long term system capabilities at a minimum reasonable cost including the costs associated with the installation, servicing and upgrading of the transmitters over the life of the system as a whole.